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Show (Edited by G. DouSla3 Wardrop. Editor of Radio Merchandising.. ! i' J - ' ' ' ;?H Radio Station at the University of Illinois Part of Broadcasting Studio, Transmitter and Power Room All in One. Success of tlie noncarrier wave system sys-tem of broadcasting, which was developed de-veloped by H. A. Brown and C. A. Keener, members of the electrical engineering en-gineering staff of the University of Illinois, is announced as positive after another series of tests which bore out the results of previous tests held over' a period of more than a year. The elimination of "fading" is an added feature of the new broadcasting system which now seems possible. In the last series of tests, instruments which accurately measured the curve of audibility of both the carrier wave system and the new noncarrier system were set up a distance of 100 miles from station WHM, the university's radiophone with which the experimental experimen-tal work is carried on. These instruments instru-ments showed the usual fading when the old system was used, but did not vary a particle when the noncarrier was employed. However, this advantage advan-tage is not yet being claimed, because It has not been subjected to enough tests to establish it as a fact. Previous advantages which were claimed for the system and which the final tests show as outstanding over the system now in general use include increased sending efficiency, more selective se-lective tuning at the receiver with greater possibility to tune out local stations, opportunity to cover greater distances and the elimination of all sorts of sounds which are impressed on the carrier wave and which only perfect modulation at the transmitting end and perfect detection at the receiver re-ceiver can eliminate. The suppressed carrier or noncarrier system differs from the present type of broadcasting in that the carrier waves go out only when a note is sounded or a syllable spoken. Between Be-tween notes or spoken words, the carrier car-rier wave does not go through the air. That is, the sound and the wave' on which it rides leave the broadcasting apparatus simultaneously. This interval in-terval of time between sounds when there is -no carrier wave In the air makes possible the advantages noted. |